Different sources, different dates/years/names/info... There are still a whole lot of unclear matters regarding Russian silver, especially with the working periods. Nothing new with that. You are very well aware of that fact. I know about 200 mistakes, faults, imperfections, misunderstandings etc. in Postnikova. Take a look at page 201. There are more errors than correct information on that page only, not to talk about other pages. What guarantees that her year 1899 is more correct that differing years in other sources?